1. Field of the Invention
The present invention relates to a piezoelectric vibrating reed and a piezoelectric vibrator.
2. Description of the Related Art
In a cellular phone or a portable information terminal device, a piezoelectric vibrator formed of a crystal or the like is used as a time source, a timing source of a control signal, a reference signal source and so on. As one of these types of piezoelectric vibrators, a piezoelectric vibrator which houses a piezoelectric vibrating reed in a vacuum sealed cavity is known. In the piezoelectric vibrator, a voltage is applied to an excitation electrode formed in vibrating arms, thereby vibrating the vibrating arms with a predetermined resonance frequency.
Incidentally, inclined surfaces (tapers) are formed at base end portions of vibrating arms connecting to a base in the piezoelectric vibrating reed. The effect of improving the strength in the vibrating arms can be expected by this structure.
As disclosed in, for example, JP-A-2008-219066 (Patent Document 1), there is known a type of piezoelectric vibrator in which a pair of support arms are provided so as to extend from a base to which a pair of vibrating arms are connected to both sides of the vibrating arms and the piezoelectric vibrating reed is mounted by the vicinity of tip ends of these support arms. The piezoelectric vibrating reed has a pair of inclined surfaces which are approximately symmetrical with respect to a center line which equally divides the vibrating arm in the width direction at the base end portion of the vibrating arm as shown in FIG. 1 of the document.